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Impact and Crash Worthiness Testing

The impact resistance of a device or structure is important for many industries where devices/components can be exposed to impact events or where devices/components are subject to abuse. Examples of impact include:

  • Aerospace structures (fuselage, wings, canopy etc) by debris (tools...)
  • Composite pipes with spanners or equipment
  • Automotive structure with solid object – crash protection for occupants
  • Dropping of portable devices (e.g. mobile phones, medical inhalers etc)

Impact events can have a detrimental effect on the future performance of the device/component/structure. In addition, impact on materials that have been aged can identify a material's toughness and its ductile to brittle transition point.

MERL has developed specialist impact test facilities to enable a variety of tests to be performed on materials, components, devices or structures.

The test facilities at MERL materials testing laboratories are complemented by the finite element analysis capabilities at MERL - which offers:

  • Simulation of high rate impact of model components and structures to predict localized deformations and failure
  • Materials model derivation at high loading rates
  • Validation of materials models at high loading rates
  • Design optimization to reduce product development costs

Drop weight testing

The MERL drop weight impact rig consists of a vertical drop sled which falls under gravity, guided on rails using low friction linear bearings. Sled velocities, at impact, can be up to 11.3 m/s (40 k.p.h.).

For adhesive joint testing the sled is instrumented with:

  • A load cell - recording inertial force within the system
  • Two accelerometers recording decelerations above and below the adhesive joint



The figure above shows the first 3.5 milliseconds of load and acceleration traces obtained during impact of a lap shear test sample. A custom Labview® program controls data collection and recording.

Modifications to the rig allow impact testing of components, whereby a drop mass or indentor falls onto a static specimen.

Servo-hydraulic impact test
 
 

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Materials Engineering Research Laboratory Limited is Wilbury Way,
Hitchin, Hertfordshire, UK, SG4 0TW.
Registered in England. Company registration number: 2015020.

Tel: +44(0)1462 427 850
Polymer Engineering, Testing, Inspection, Research and Development, UK